Electric switch



March 10, 1942. H 2,275,853

ELECTRIC SWITCH Filed April 1, 1941 Inventor.- hmp Hutt; b WW6 .y.

His Attorney troller.

Patented Mar. 10, 1942 UNITED STATES PATENT OFFICE ELECTRIC SWITCHPhilip Hutt, Milford, Conn., assignor to General Electric Company, acorporation of New York Application April 1, 1941, Serial No. 386,249

(or. zoo-152) 4 Claims.

My invention relates to electric switches and more particularly toelectric switches of the type having liquid contact circuit controllers.

The object of my invention is to provide an improved construction andarrangement in switches of this type, the improvement relatingparticularly to the operating mechanism for the liquid contact circuitcontroller.

In the accompanying drawing, Fig. 1 is a plan view of a switch embodyingmy invention; Fig. 2 is a view of the interior of the switch the casingbeing shown in section; Fig. 3 is another view. of the end of the switchpartly in section; and Fig. 4 is a perspective view of the liquidcontact circuit controller and a portion of the operating mechanism.

Referring to the drawing, I have shown my invention applied to a switchincorporating a rotatable liquid contact circuit controller. Such aswitch is shown in the Sambleson Patent .No. 2,142,153, dated January 3,1939, which is assigned to the same assignee as the instant invention.Theswitch includes a housing It of insulating material, such as a moldedplastic, which is provided with a recess ii to receive a liquid contactcircuit controller l2 in the form of a mercury button. The buttoncomprises two opposed cup-shaped metal terminals i3 separated by a glassbead l4 and an interior insulating barrier (not shown) provided with anorifice which separates the mercury contained within the button into twoparts except when the orifice is immersed in the conducting liquid; theinterior construction of the mercury button is more fully described inthe aforementioned Sambleson patent and forms no part of the presentinven tion.

The circuit controller I2 is supported between spaced contact arms I 5located in the recess H. Each contact arm is provided with a bearingsurface at one end which is seated in a recess in a correspondingcup-shaped terminal so that the mercury button is securely supportedbetween the contact arms. formed with a terminal portion is extendingoutside the recess which is provided with a terminal screw ii forconnection to an electrical circuit. An operating handle I8 is formedwith projections which engage complementary notches i5 formed in each ofthe cup-shaped terminals I3 so that the circuit controlleris rotatedupon movement of the handle. The inner wall of the handle has a recessformed therein to provide clearance for the bead ll of the circuit con-At its other end each arm is The operating handle and circuit controllerare held in assembled relationship by means ofspring strips 2| securedin any suitable manner, as by spot welding, to a mounting strap 22which,

in turn, is secured to the housing by drive screws 23. The spring strips2! bear against abutments 24 on opposite sides of the handle and hold itfirmly in engagement with the button. The circuit controller isprevented from moving downwardly out of engagement with the supportingarms i5 by a bearing surface 25, upstanding from the bottom of therecess, over which the periphery of the button slides. Offset surfaces26 formed in opposite ends of the strips 2| limit movement of the handleand button ineither direction. The switch thus far described issubstantially the same as that shown and described in the aforementionedSambleson patent.

In the construction of the switch of the Sam- 'bleson patent theprojections on the handle which engage the notches in the circuitcontroller are located centrally of the handle and the widened portionsat the base of the handle extend on each side of the projections incontact with the pe- 1 riphery of the button giving, in efiect, threepoints of contact between the button and the handle. While ingeneralthis arrangement provided a proper connection between the circuitcontroller and handle I found that it had several drawbacks. It theprojections on the handle were too long or the notches in the button tooshallow, by a few thousandths of an inch, then the widened or flangedportions at the base of the handlewould not make contact with thesurface of the button and the handle would rock relative to the buttonabout the projections as a pivot. On the other hand, if the projectionswere too short 'or the notches too deep, the handle would rest on theflange portions and the projections would slide in the notches causinglost motion between the controller and handle.

In either case a certain amount of objectionable play occurred betweenthe controller and handle making the switch noisy. Also the circuitcontroller might -not be moved to full circuit closing position.

My invention overcomes these deficiencies by providing a construction inwhich lost motion and provide cooperating bearing surfaces at the otherend. Referring to Figs. 2 and 4 of the drawing, I provide projections 21at one endof the flange 28 of the handle which cooperate with thenotches l9 formed in the terminal members ll. At the other end of theflange I provide bearing surfaces 29 which rest on the peripheries ofthe terminal members; as shown in Fig. 2. This arrangement gives, ineffect, a two-point support for the handle on the mercury button andeliminates the objectionable so-called three point support of priorconstructions. The intermediate curved portion 30 of the handle flangeis spaced from the periphery of the mercury button so that the handlecontacts the button.

only at the points 21 and 29. This means that the spring strips 2| holdthe handle firmly in engagement with the mercury button withoutpossibility of lost motion occurring between the handle and button. Thisresults in a switch which is exceptionally silent and in which thecircuit controller may be accurately positioned by the handle at alltimes. v

V What I claim as new and desire to secure by Letters Patent of theUnited States is:

1. In an electric switch, spaced contact members, a liquid contactcircuit controller having terminals engaging said contact memberssupporting the controller for rotation, a portion of said circuitcontroller being provided with a notch and a handle having a projectionseated in'said notch and having a bearing portion spaced from saidprojection engaging the periphery of said circuit controller, theportion of the handle between said projection and bearing portion beingspaced from contact with the periphery of said circuit controller.

2. An electric switch comprising a rotatably mounted liquid contactcircuit controller, an operating handle, said circuit controller beingprovided with-a notched portion, said handle being formed with aprojection seated in said notch andlikewise being provided with abearing portion resting on the circuit controller at a point spacedcircumferentially from' said notch, the portion of the handleintermediate said projection and bearing portions being spaced fromcontact with the periphery of said circuit controller, and spring meansbiasing said operating handle into engagement with said circuitcontroller whereby the circuit controller is rotated in response tomovement of the handle.

3. In an electric switch, spaced contact members, a liquid contactcircuit controller having terminals engaging said contact membersupporting the controller for rotation, an operating handle, saidcircuit controller being provided with a notched portion, said handlebeing provided with a projection seated-in said notch, said handlelikewise being formed with a bearing portion spaced from said projectionand engaging the periphery of said circuit controller at a point spacedcircumferentially from said notch, the intermediate portion of thehandle between said projection and said surface being spaced out ofcontact withthe periphery of said circuit con troller, and spring meansmaintaining said handle in seated engagement on said circuit controllerwhereby said circuit controller is rotated in response to movement ofsaid handle.

4. An .electric switch comprising a pivotally mounted circuit controllerand an operating handle therefor, intcrengaging notched-portions on saidcircuit controller and handle, said handle being formed with a bearingportion engaging the circuit controller. at a point spaced from the saidnotched portions, the portion of the handle between said notchedportions and said bearing portion being spaced from and out ofengagement with the circuit controller, and means maintaining the handlein engagement with the circuit controller whereby said circuitcontroller is actuated in response to movement of the handle.

' PHILIP HUTT.

